Veho Muvi Drone Self-Tightening Propellers, 4 Pack Compatible with the Muvi Drone series Self-tightening design stops the propellers from becoming loose during operation and also prevents over-tightening Innovative design prevents incorrect installation of the propellers on the motors Made from hard-wearing plastic for stable flight Includes two 10" clockwise self-tightening propellers and two 10" anti-clockwise self-tightening propellers